Tire size? New twist to an old question.

[6shark9]

As you can see I need a new set.

What I want to do is fill the wheel wheels with bigger tires and improve the ride.
Shown on the CAR ('69) are 225 60 15 (Merit brand, kinda meaty for a 225 - 8" tread)

I'd be happy with 225 70 15 filling the wells, improving the ride, and correcting the speedo. But those size Radial T/As are a lot skinnier.

The TT IIs appear to have a 3 1/2" backspacing. And I have about 1" of clearance on the inside of the rear tires.

If you have had a similiar experience let me know what size tires I can get away with based on the pics and info.

Many Thanks!

 

[kiwi vet]

Tire Options

Hey 6shark9

Your standard 225 70 15's = 696mm diameter (sorry were metric here) I think thats about 27.4 inches based on 25.4mm = 1 inch.
The current ones you have are 225 60 15 = 651mm dia or 25.6 inches dia.
You say these are to small, Therefore options are

A 255 60 15 = 687mm dia. or 27.04 inches dia.

A 265 60 15 = 699mm dia or 27.5 inches dia.

Both fill guards better, one slightly under standard, one slightly over.

Hope this helps.

Grant

 

[6shark9]

Thanks.

Yes, the 27.4" diameter is what I'm after, However....

What is the widest tire that the provided pics and info might allow.
245 60 15?
255 60 15?

I can give up some diameter for the wider 245 60 15 (if they fit)


The 225 60 15s are pretty much flush with the edge of the fender (yes, there is a pivot action that allows the tire to rotate inside the fender under load)

I have 1" of clearance on the inside of the rear tires.

(225 to 255 is an additional 30mm, with 15mm each side, then my clearance goes to about 7/16-3/8" or 10 mm - that's gonna rub! with tire and suspension flex)

 

[kiwi vet]

Thanks.

Yes, the 27.4" diameter is what I'm after, However....
Yes
What is the widest tire that the provided pics and info might allow.
245 60 15?
255 60 15?
Hard to say without seeing the actual, sorry forgot 68/69 have narrower guards, as 255 fac.option on later C3's.
I can give up some diameter for the wider 245 60 15 (if they fit)
Yes, choice is personal.
The 225 60 15s are pretty much flush with the edge of the fender (yes, there is a pivot action that allows the tire to rotate inside the fender under load)
I have 1" of clearance on the inside of the rear tires.
(225 to 255 is an additional 30mm, with 15mm each side, then my clearance goes to about 7/16-3/8" or 10 mm - that's gonna rub! with tire and suspension flex)

I think the easiest way to know for sure, is get hold of an old second tire in the 255 or 265 size and mount it, try it on the different corners and allow for additional tread (this is diameter only). This will confirm width issue at least under driving conditions for clearances. Note manufacturers tires vary on width by model, so make sure the test tire is the model you are thinking of.
Hope this helps.
Good luck
Grant

 

[JOE BYRNE]

Tire size

Maybe Im old fashioned but my 225 70 15's seem to fill my wheel wells just fine. Thats what came on the car and I would not want anything bigger than that. Only my opinion!!

Joe

 

[ernie d]

Hey shark,

on my 69 coupe I have 245 60 15, they are perfect. Fill the space perfectly, nice ride, and the width is perfect.
​

 

[Crimson Thunder]

I agree with Ernie D. I also have 245 60 15's and i think the fit is perfect.they are about an inch shorter than the 225 70 15 but wider.they fill the wheelwell perfectly.

 

[6shark9]

Excellent! Thanks folks.

The tire places are more than willing to mount other sizes to check fit.
I want to limit the choices so I'm going to look at the 225 70 and the 245 60 as my options.

Finding (4) 245 60s in stock might be tough.

 

[TJay]

Finding (4) 245 60s in stock might be tough.

On 2 of my Corvettes (72 & 79) I'm running 245X60 front and 255X60 rear (stock ralley rims 15X8) without any issues in fit, ride or handling. Hope this is another consideration for you.

 

[Buckskin7T7V]

On my 77 I run 245/60/15 on the front and 255/60/15 on the rear, it works and looks good.